16.4.1.24 Replication and the Query Optimizer

It is possible for the data on the master and slave to become
different if a statement is written in such a way that the data
modification is nondeterministic; that is, left up the query
optimizer. (In general, this is not a good practice, even
outside of replication.) Examples of nondeterministic statements
include DELETE or
UPDATE statements that use
LIMIT with no ORDER BY
clause; see Section 16.4.1.15, “Replication and LIMIT”, for a
detailed discussion of these.